Bags with sealing profiles are used wherever frequent opening and closing is required. Therefore it is conceivable, for example, to store food such as chips or cereals in this type of bag. In order to further simplify the handling of such bags, a slide may additionally be provided on the complementary sealing profiles for opening and/or closing the bag.
A bag that is provided with a reclosable seal is known from U.S. Pat. No. 6,308,498 B1. Here, a bag is described where the reclosable seal is welded to the inner bag side walls and the bag walls completely enclose the reclosable seal. The reclosable seal is formed by complementary sealing profiles and a perforated connecting piece linking the sealing profiles. When the bag is torn open, first the perforation line, meaning the connection between the two profiles, is detached, then the two sealing profiles are separated and finally the two connected side pieces are torn apart on one side. In order to close the bag again, the two complementary sealing profiles are pressed into one another again.
In order to avoid having to work with pre-manufactured bags, so called form, fill and sealing machines (FFS) were developed. A machine of this kind is described in the European patent application EP 1 099 636 A2. In form, fill and sealing machines of this type, the plastic film that is used to make the bag is directly rolled off a reel and fed into the bag production machine. In the embodiment described, the plastic film is first formed, meaning folded around its centerline, and subsequently a reclosable seal is welded to the fold or inside the open foil panel. After transverse welding, the bag is open on one side and may be filled. Subsequent to filling, the bag is sealed by another longitudinal weld. For opening and closing of the bag, a slide is mounted on sealing elements.
Since the filling and production of the bag is performed horizontally, these machines are called horizontal form, fill and sealing machines.
One example of a vertical FFS machine is described in EP 0 994 772 B1. A method for the automatic production of bags with matching closure profiles is described. The plastic film unwound from the reel is guided over a forming shoulder and subsequently welded to a closure assembly consisting of sealing profiles and a closing element. Directly following the forming and welding of the closure assembly and the creation of a transverse weld, the bag is filled with product by means of a filling chute. The closure assembly for resealing the finished bag is fed as a separate component and first has to be torn open during initial opening of the bag, since the closure assembly is designed closed facing the inside of the bag.